Biofouling is the buildup of organisms like algae and barnacles on submerged marine vessels. Biofouling increases frictional drag, fuel consumption and leads to migration of marine species into non-native environments. In the past, to combat BF, antifouling coatings containing tin or copper biocides were used. Toxicity of the coatings to non-target organisms has led to their replacement with elastomeric FR coatings. To overcome the lack of strength of the commercial FR coatings, self-stratified FR coatings, based on siloxane (PDMS) and polyurethane (PU), were developed in the Webster group. Further research showed that some organisms (Such as barnacles) attached strongly to hydrophilic surfaces while other organisms (Diatoms) preferred attachment to hydrophobic surfaces. Therefore, a combination of PEG and PDMS was required to understand an amphiphilic effect on the marine organisms. In one such attempt, Amphiphilic siloxane-polyurethane (AmSiPU) coatings were prepared using polyisocyanate modified with polyethylene glycol (PEG) and polydimethyl siloxane (PDMS) of varying molecular weights with, catalyst, solvent, acrylic polyol, and pot life extender. The pre-polymers of modified polyisocyanate with PDMS and PEG were characterized with Fourier Transformed Infrared Spectroscopy (FTIR) and isocyanate titrations. The pre-polymers were then integrated into coatings and characterized using mechanical testing. The resultant coatings showed high FR towards bacteria, diatoms, green algae, and barnacles. These AmSiPU compositions displayed similar or better FR performance to several of the latest commercial standards. These coatings also had the additional benefits of high mechanical strength and adhesion to primed substrates. Water contact angle was measured to reveal the coatings undergoing rearrangement at the surface with the introduction of water.

Amphiphilic polyurethane coatings for fouling release applications

253rd National Meeting (2017)

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